A Brooklyn teen yesterday took the stand against a prominent Orthodox Jewish leader accused of sexually abusing her — and her gripping testimony provided a rare glimpse into a cloistered Hasidic community.

The now-17-year-old girl was just 12 when Rabbi Nechemya Weberman (pictured), 54, began abusing her after her parents sent her to him for counseling because she wasn’t following the strict rules of her ultra-religious Satmar sect, prosecutors say.

The pretty blond — whose testimony brought some female Orthodox observers in the courtroom to tears — told the Brooklyn Supreme Court jury about the school discipline problems that led her parents to bring her to Weberman.

“You had to wear tights that are very thick so there’s no way anybody can see your legs,” she said. “I was sent to the principal’s office every day because my tights weren’t thick enough.”

She said her father decided she needed the counseling because he thought she had spoken to a neighborhood boy, and she asked teachers questions like, “How do you know God exists?”

Because the Satmar sect provides no sexual education to women until just before they marry, the teen said, she didn’t understand what Weberman was doing during their first counseling session. It was the first time she had been touched by a male outside her family, she said.

The teen said her parents brought her to a rabbinical court in an unsuccessful attempt to convince her to drop the charges.

About 50 Orthodox Jews, many of them her supporters, packed the courtroom to capacity. Women in long dresses cried during the graphic testimony.

“The community needs to understand you can’t cover up sexual abuse anymore,” said Ari Rubinstein, 42, an Orthodox Jew from Kensington who watched the testimony yesterday.

“If the community sees him go down, they’ll realize they have to take action. It’ll be a wake-up call.”

The teen recently married, and plans to start college next year. She wore a Star of David necklace and black Ugg boots to court

Defense lawyers say their client is innocent and have argued that the teen is accusing Weberman only to retaliate for a bizarre incident in which he and her father secretly filmed her having sex with her boyfriend in an attempt to file statutory-rape charges.